INFORMATION:
Text: Paul Scherrer Institute/Sebastian Jutzi
About PSI
The Paul Scherrer Institute PSI develops, builds and operates large, complex research facilities and makes them available to the national and international research community. The institute's own key research priorities are in the fields of matter and materials, energy and environment and human health. PSI is committed to the training of future generations. Therefore about one quarter of our staff are post-docs, post-graduates or apprentices. Altogether PSI employs 2100 people, thus being the largest research institute in Switzerland. The annual budget amounts to approximately CHF 400 million. PSI is part of the ETH Domain, with the other members being the two Swiss Federal Institutes of Technology, ETH Zurich and EPFL Lausanne, as well as Eawag (Swiss Federal Institute of Aquatic Science and Technology), Empa (Swiss Federal Laboratories for Materials Science and Technology) and WSL (Swiss Federal Institute for Forest, Snow and Landscape Research).
Contact
Prof. Urs Baltensperger
Laboratory for Atmospheric Chemistry
Paul Scherrer Institute, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
Telephone: +41 56 310 24 08;
e-mail: urs.baltensperger@psi.ch
[German, English]
Dr. Houssni Lamkaddam
Laboratory for Atmospheric Chemistry
Paul Scherrer Institute, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
Telephone: +41 56 310 42 04;
e-mail: houssni.lamkaddam@psi.ch
[English, French]
Dr. Imad El Haddad
Laboratory for Atmospheric Chemistry
Paul Scherrer Institute, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
Telephone: +41 56 310 29 95;
e-mail: imad.el-haddad@psi.ch
[English]
Original publication
Large contribution to secondary organic aerosol from isoprene cloud chemistry
H. Lamkaddam, J. Dommen, A. Ranjithkumar, H. Gordon, G. Wehrle, J. Krechmer, F. Majluf, D. Salionov, J. Schmale, S. Bjeli?, K. S. Carslaw, I. El Haddad, U. Baltensperger
Science Advances, 24.03.2021
DOI: 10.1126/sciadv.abe2952
Aerosol formation in clouds
2021-03-24
(Press-News.org) Researchers at the Paul Scherrer Institute PSI have studied for the first time how chemical reactions in clouds can influence the global climate. They found that isoprene, the dominant non-methane organic compound emitted into the atmosphere, can strongly contribute to the formation of organic aerosols in clouds. They published their results today in the journal Science Advances.
Aerosols, a mixture of solid or liquid particles suspended in the air, play an important role in Earth's climate. Aerosols originate either from natural or human sources. They influence Earth's radiation balance by interacting with sunlight and forming clouds. However, their effect remains the single most significant uncertainty in climate models.
One substance that is very common in the atmosphere is isoprene, an organic compound whose reactions in the gas phase are relatively well understood. Isoprene is given off by trees and can produce aerosols when it is oxidised. How isoprene and its reaction products react in cloud droplets is still largely unknown. That's why researchers at the Paul Scherrer Institute PSI have used a type of flow reactor with wetted walls, together with the most advanced mass spectrometers, to investigate what could be happening chemically inside clouds for the first time under atmospherically relevant conditions.
"Our experimental setup allows us for the first time to precisely investigate the distribution of organic vapours at the air-water interface under near-environmental conditions," says Houssni Lamkaddam, a researcher in the Laboratory of Atmospheric Chemistry at PSI. "With our apparatus, we can now simulate what happens in clouds."
What exactly happens in clouds?
In the special apparatus, a so-called wetting reactor, a thin film of water is maintained on the inside of a quartz tube. A gas mixture containing, among other substances, isoprene, ozone, and so-called hydroxyl radicals is fed into the glass cylinder. UV lamps are installed around the glass cylinder to simulate daylight conditions for some of the experiments.
Using this setup, the researchers found that up to 70 percent of the isoprene oxidation products can be dissolved in the water film. The subsequent aqueous oxidation of the dissolved species produces substantial amounts of secondary organic aerosols. On the basis of these analyses, they calculated that the chemical reactions that take place in clouds are responsible for up to 20 percent of the secondary organic aerosols on a global scale.
"This is another important contribution to a better understanding of the processes in the atmosphere," sums up Urs Baltensperger, scientific head of the Laboratory of Atmospheric Chemistry at PSI. Earth's radiation balance is a very important factor in the entire climate process and thus also in climate change. "And aerosols play a crucial role in this," says the atmospheric scientist. While aerosols form cloud droplets, this research shows that clouds can also form aerosols through the aqueous chemistry of organic vapours, a process that is well known with regard to sulfate aerosols but here is also shown for the organic fraction. This new experimental setup, developed at PSI, opens up the possibility of investigating aerosol formation in clouds under near-atmospheric conditions so that these processes can ultimately be included in climate models.
ELSE PRESS RELEASES FROM THIS DATE:
New cancer immunotherapy recruits help from lymphatic vessels
2021-03-24
CHICAGO -- Immunotherapy, which recruits the body's own immune system to attack cancer, has given many cancer patients a new avenue to treat the disease.
But many cancer immunotherapy treatments can be expensive, have devastating side effects, and only work in a fraction of patients.
Researchers at the Pritzker School of Molecular Engineering at the University of Chicago have developed a new therapeutic vaccine that uses a patient's own tumor cells to train their immune system to find and kill cancer.
The vaccine, which is injected into the skin just like a traditional vaccine, stopped ...
An overlooked strand of the Southern San Andreas Fault may pose a major earthquake risk
2021-03-24
Addressing uncertainties about where large earthquakes are most likely to occur along the southern San Andreas fault, which splits into multiple strands east of Los Angeles, a new study identifies a strand that has largely flown under the radar of public concern as the region's greatest earthquake threat. The study determines that the Mission Creek strand, which passes through major water and power infrastructure for the greater Los Angeles region, may account for almost the entire slip rate of this portion of the fault, suggesting it may actually be the primary Pacific-North American plate boundary fault at this latitude. The San Andreas fault threatens large future earthquakes, since its southernmost section has not ruptured in almost 300 years ...
Greenland caves: Time travel to a warm Arctic
2021-03-24
A 12-centimetre-thick sample of a deposit from a cave in the northeast of Greenland offers unique insights into the High Arctic's climate more than 500,000 years ago. The geologist and cave scientist Prof. Gina Moseley collected it during an exploratory expedition in 2015 for her palaeoclimatic research in one of the most sensitive areas of the world to climate change. The cave is located at 80° North 35 km from the coast and 60 km from the Greenland Ice Sheet margin. It was part of the Greenland Caves Project, funded by 59 different sponsors including the National Geographic Society. Moseley and her team are interested in the climate and environmental history captured by the unique cave deposit. "Mineral deposits formed ...
Approved medications preserve platelets and protect mice from bacterial blood infections
2021-03-24
A study of 49 patients reveals that toxins from the bacterial pathogen Staphylococcus aureus can destroy the body's blood-clotting platelets, raising the risk of death during bacterial blood infections. Further experiments in mice also showed that the approved drugs ticagrelor and oseltamivir protected platelets and helped treat infections, suggesting these compounds could be repurposed into badly needed therapies for blood infections. Bacterial blood infections have mortality rates as high as 20% to 30% even with supportive care, and these rates have remained high for decades. Blood infections can also cause complications such as sepsis and endocarditis, and the rise of multidrug resistance has only compounded what was already a serious ...
Exploiting cancer cells to aid in their own destruction
2021-03-24
Immunotherapy, which recruits the body's own immune system to attack cancer, has given many cancer patients a new avenue to treat the disease.
But many cancer immunotherapy treatments can be expensive, have devastating side effects, and only work in a fraction of patients.
Researchers at the Pritzker School of Molecular Engineering at the University of Chicago have developed a new therapeutic vaccine that uses a patient's own tumor cells to train their immune system to find and kill cancer.
The vaccine, which is injected into the skin just like a traditional vaccine, stopped melanoma tumor growth in mouse models. It even worked long-term, destroying new tumors long after the therapy was given.
The results were published ...
Green leafy vegetables essential for muscle strength
2021-03-24
Eating just one cup of leafy green vegetables every day could boost muscle function, according to new Edith Cowan University (ECU) research.
The study, published today in the Journal of Nutrition, found that people who consumed a nitrate-rich diet, predominantly from vegetables, had significantly better muscle function of their lower limb.
Poor muscle function is linked to greater risk of falls and fractures and is considered a key indicator of general health and wellbeing.
Researchers examined data from 3,759 Australians taking part in Melbourne's Baker Heart and Diabetes Institute AusDiab study over a 12-year ...
Stay on track! Support system to help the visually impaired navigate tactile paving
2021-03-24
Sight is by far the sense that we humans use the most when navigating an environment. When those who are blind or visually impaired walk alone, they put themselves at great risk of falling or colliding with obstacles, especially when traversing new places. Unfortunately, the number of visually impaired people throughout the world is likely to increase in the near future because of the rapidly aging population. Thus, there is an urgent need for innovative and cost-effective solutions to help visually impaired people navigate safely.
A promising strategy that was first implemented in Japan and then replicated throughout the world is called tactile paving. Inspired by Braille, the reading system of the blind, tactile paving essentially consists of ...
'Silencing' protein to weaken COVID-19
2021-03-24
When invaded by a virus, our body cells launch an alert to neighboring cells to increase their antiviral defenses to prevent the infection from spreading. Some viruses, however, manage to bypass this system by mimicking the host's RNA, preventing them from being detected by the infected cell and avoiding this alert. In the case of SARS-CoV-2, this mimicking uses a protein known as nsp14. This protein is also very important for virus multiplication, a task which is facilitated by its binding to the nsp10 protein, resulting in a protein complex. Interfering with nsp14 binding and with the nsp10-nsp14 protein complex is the aim of the most recent ITQB NOVA research in COVID-19, led by researchers Margarida Saramago, Rute Matos and Cecília Arraiano.
The researchers ...
Photosynthesis could be as old as life itself
2021-03-24
Researchers find that the earliest bacteria had the tools to perform a crucial step in photosynthesis, changing how we think life evolved on Earth.
The finding also challenges expectations for how life might have evolved on other planets. The evolution of photosynthesis that produces oxygen is thought to be the key factor in the eventual emergence of complex life. This was thought to take several billion years to evolve, but if in fact the earliest life could do it, then other planets may have evolved complex life much earlier than previously thought.
The ...
New machine learning tool diagnoses electron beams in an efficient, non-invasive way
2021-03-24
Beams of accelerated electrons power electron microscopes, X-ray lasers, medical accelerators and other devices. To optimize the performance of these applications, operators must be able to analyze the quality of the beams and adjust them as needed.
For the past few years, researchers at the Department of Energy's SLAC National Accelerator Laboratory have been developing "virtual diagnostics" that use machine learning to obtain crucial information about beam quality in an efficient, non-invasive way. Now, a new virtual diagnostic approach, published in Scientific Reports, incorporates additional information about the beam that allows the method to work in situations where conventional ...